The Sun Bin bingfa 孫臏兵法 "The Art of War by Sun Bin" is a military classic from ancient China which had been thought lost. It was rediscovered in 1972.
The Sun Bin bingfa, in ancient times also called Qi Sunzi 齊孫子 "Master Sun from the state of Qi", stood in the tradition of China's oldest military classic, the Sunzi bingfa 孫子兵法. Sun Bin 孫臏, the putative author, is said to have been a descendant of Sun Wu 孫武, the great Master Sun. Bin is not the real name of the person, but an epithet given to him after he had been punished by cutting off his kneecaps (bin 臏). Sun Bin studied the art of war by the general Pang Juan 龐涓 and Master Guiguzi 鬼谷子. Pang Juan was envious of Sun Bin's skills and slandered him with the ruler of Wei 魏. After being punished cruelly, Sun Bin escaped to the state of Qi, where he served King Wei 齊威王 (r. 378-343) and undertook some very successful campaigns against Wei, together with general Tian Ji 田忌. Sun Bin's military tactic was to attack that part of the inimical army that was weak and which was in high need of support by other parts of the corps, which therefore would not be able to exhibit its full strength at all parts of the battle array. His strategy was to encircle Wei and to support the state of Zhao 趙. Later on he had to leave Qi and went to the state of Chu 楚 where he eventually died. Some later scholars even state that Chu had been his home state. Sun Bin was very famous in ancient times and is mentioned side by side with Wu Qi 吳起, general in the state of Wei.
In the imperial bibliography Yiwen zhi 藝文志 in the official dynastic historyHanshu 漢書, the Qi Sunzi is mentioned as a book with 19 chapters and 4 juan "scrolls" of illustrations. The book must have still been in circulation after the Han period 漢 (206 BCE-220 CE) but was already lost during the mid-Tang period 唐 (618-907). It is quoted in Cao Cao's 曹操 commentary to the Sunzi bingfa (3rd cent. CE), in Zhao Rui's 趙蕤 Changduanjing 長短經 and Du You's 杜佑 encyclopediaTongdian 通典.
In 1972, a Han period tomb library was unearthed in Yinqueshan 銀雀山 near Linyi 臨沂, Shandong. On the bamboo slips, a version of the Sun Bin bingfa was preserved. The version is written down on 364 slips and included 15 chapters on 2 juan. In the first part, the personal history of Sun Bin, as well as his most important statements, are recorded, while the second part contains military treatises by Sun Bin, which are presented in a quite confuse manner and not systematically arranged. In 1985 the text was republished after revision, and was supplemented by another chapter, the Wuxiaofa 五教法. The reconstruction of the text on the highly damaged bamboo slips was only possible with the help of quotations from the Sun Bin bingfa in other books. The chapters of the first part can clearly be identified as part of the Qi Sunzi, while those from the second part can not be attributed to a concrete military classic. Some parts prove that it belongs to the tradition of the Sunzi bingfa, while others are more near to other late Warring States period 戰國 (5th cent.-221 BCE) military writings like the Weiliaozi 尉繚子 or Liutao 六韜. The bamboo slips were, according to hints in the content, probably written during the reign of King Xuan of Qi 齊宣王 (r. 342-324).
In the text, the authors stress the importance of military action for the survival of the state, and renounces the Confucian values of ritual, etiquette and kindheartedness. A strong military can only be established, if the state is rich enough to support is troops. The troops themselves have to be trained, have to be disciplined by military rules, and have to be led by an able commander. Victory lies in the selection of valiant troops, and their bravery lies in their discipline. Discipline can only be enforced by the right application of reward and punishment. The commander must have the virtue of charisma, trust, loyalty and respect. He must know how to formation his troops, how to use their strengths, how to change the tactics according to circumstances, and how to use chances in battle. The selection of the right persons is most important for a successful army. A general has to know the way of Heaven (weather), the patterns of the earth (topography), he must possess the hearts of his troops, to know the enemy and how to make use of the eight different battle arrays. Preparation of a battle is almost more important than fighting itself. Before a strong enemy, the own troops have to exhibit power; in the face of a weaker enemy, one has to feign weakness oneself; and an equally strong enemy has to be incited to disperse his forces before attacking him with concentrated forces. Sun Bin also compares military activities with the Five Processes in correlative thinking.